Propeller feathering control



sept. 16, 1947. E. MARTIN Y 2,427,567

PROPELLER FEATHERING' CONTROL I Filed Oct. 27,41939 2 Sheets-Sheet 1 66 IHIl lul 43 A INVENTOR /50 /54 36 [5:2 EreM-artin A'FI'ORN EY 2 sheets-'sheet 2 1% Nw Kv# Lg.

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INVENTOR y E'TEIHI'ZZM B/m Sept. 16, 1947. E. MARTIN PROPELLER FEATHERING CONTROL I Filed oct. 27, 193s ATTORNEY Patented Sept. 16, 1947 raoratmin lFEATHnaILNd contraer.

Erie Martin, West Hartford, Conn., assignor to ilnited Aircraft Corporation, East Hartford,

Conn., a corporation of Delaware' Application October 27, 1939, Serial No. 301,539 Claims. (Cl. 121-33) This invention relates to improvements in propeller control means and has particular reference to an improved means for controlling the feathering and unfeathering operations of a hydro-controllable propeller.

An object of the invention resides in the provision of improved means for controlling the/application of hydraulic duid under pressure to a hydro-controllable propeller to feather or unfeather the saine in such a manner that the application of the hydraulic rluid under pressure will be discontinued when the feathered or unfeathered condition of the propeller is reached.

A further object resides in the provision of an improved control of the chc-tracterv indicated which is responsive to a physical characteristic of the hydraulic fluid such as the pressure or rate of ow to control the featherino and 'unfeathering operations of the propeller.

A still further object resides in he provision of a hydraulic propeller control or" the character indicated which is small and compact so that it may be installed in the cockpit within easy reach 0f the pilot Without taking up an unreasonable amount of space and which requires no further attention from the pilot once it has beenv'set to bring about the propeller position desired.

Other objects and advantages will be more particularly pointed out hereinafter or will become apparent as the description proceeds.

In the accompanying drawings in which like reference numerals are used to designate similar parts throughout there is shown a suitable mechanical construction for the purpose of disclosing the invention and one somewhat modified form thereof. The drawings, however, are for the purpose of illustration only and are not to be taken as limiting or restricting the invention since it will be apparent to those skilled in the art that various changes in the illustrated constructions may be resorted to without in any way exceeding the scope of the invention.

In the drawings,

Fig. 1 is a somewhat diagrammatic View of the pitch control mechanism for a controllable pitch propeller, the improved feathering and unfeathering control valve included therein being shown partly in section to better illustrate the construction thereof.

Fig. 2 is a diagrammatic View of a hydro-con- 2 shown in a different operative position in Fig. 3 than "the position illustrated. in Fig. 2. "Fig 4 is Vertical sectional view through an improved pitch control'valve" constructed according vto the invention.`

Fig. '5 is a vertical sectional View through a somewhat'modied form of propeller pitch control valve', and

' Fig. 6V is afragmentary view similar to a portion ol Fig. 5 showing the Valve parts in a differentoperative position.

Rei'f'larringA tothe drawings in detail, the numeral :(0 generally indicates a hydro-controllable propellerftliepitch of which is controlled in the normaler constant speed range by a governor, generally indicated at i2, and Whichrnay be brought into and out of a feathered position by thafeathering control valve generallyindicated 2141314.

VThe propeller may be such a propeller as is more 'particularly illustrated and described in my co-pendihg joint application' Serial No. 184,792, led January '13, 1938, `for Feathering propeller control, vissued on `April 21, 1942, as U. S. Patent No'. 2,280,712?, and mayV comprise in general, a pluralityof blades, as indicated at l5, rotatably mounted at their Yroot 'or' base ends in a hub struc.. ture" ld'and'rotatable about theirv longitudinal axes by a gear element 2i) which is rotated through Ya. cani iby 'means' of a piston 2t' reciprocable inthe `cylinder 26.

VThe propeller'is mounted upon a drive shaft 2S which 'contains "the distributing valve, generally indica'ted'at 33. 'When'the distributing valve is in'positio'n for constant speed control by the governor`i2',"as illustrated in Fig'. 2, the con- "duit32f leading from a suitable source of hydraulic luidnnlderpres'sure 'such as the engine lubiicatnglpun'ip gli', is connected throughV the valve' passages 35' and 38 and the conduit il@ With the space between the'"'pis`ton 2li andthe closed outerend of the cylinderZ'to exert a continuous force o'r'the pistonfli rto assist the action of centrifugal forc' acting on the blades "I6 to turn the 'blades' towards their lovv pitch position. A sevc'ond'channel 2, Vwhich may bev the space Within "the hollovv shaft "28 surrounding the tube or con'dit'ffvis connected through the oil collector ring lill and tl`ie' associated passages with a governo controlled valve, not illustrated, and leads through the valve passages iS and 48 and the conduit 5p' to the `space at the end of the piston 2 4 adjacent to the hub I8. The governor controlled valve is connected with a source of'liydraulic fluid under pressure, such as the booster 3 pump 52, which increases the pressure produced by the pump 34, and is also connected with a drain line 55 and is capable of connecting the channel 42 either with the high pressure uid source or with the drain line depending upon the demands of the speed responsive governor I2 for a higher or a lower propeller pitch. If the engine speed is too high, the governor will connect the channel 42 with the high pressure fluid source to increase the propeller pitch, and if the speed of the engine is too low, the governor will connect the channel 42 with the drain line 56 to permit the propeller pitch to decrease under the action of centrifugal force and the uid pressure supplied through the conduit 48, to correspondingly change the load on the engine and increase the engine speed.

The valve I4 is connected at one side through the conduit 58 with a source of hydraulic fluid under a pressure higher than the pressure output of the pump 52, which source has been diagrammatically represented as the pressure tank 68 which may be supplied with fluid under pressure through the conduit 52 leading from a pump or other suitable source. The valve is connected at the same time through the conduit 64 to the sump or reservoir 66. At its opposite side the valve is connected through the conduit 68 to the' control valve, generally indicated at 10, which is in turn connected with the governor actuated valve through the channel 'I2 and with the slip ring 44 through the channel or conduit 14. The Valve 'i0 may be such as is particularly illustrated and described in my co-pending application Serial No. 274,334, filed May 18, 1939, for Propeller pitch control valve, issued on June 24, 1941, as U. S. Patent No. 2,246,745, and is operative to connect the governor channel I2 with the line 14 to simultaneously block the conduit 68 from the governor and propeller pitch control conduits, when the fluid pressure in line 68 is not suflicient to open the valve. This valve also acts to cut off the channel 12 from the channel 'i4 and connect the Valve line 68 with the line 'I4 and collector ring 44 when the pressure in the line 63 exceeds the pressure developed by the governor pump 52, by an amount suiiicient to open the valve.

For a detailed description of the valve I4 reference may now be had to Figs. 4, 5 and 6.

Considering first the form of valve shown in Fig. 4, the uid pressure line 5S from the pressure source 60 leads to a chamber or bore 'i5 extending through the valve casing 18 which chamber is connected by the transverse passage 8D to the parallel bore or chamber 82 from which the line 68 leading to the propeller extends. A valve stem 84 in the chamber I6 cooperates with a valve seat 86 to separate the pressure line 58 from the transverse passage 88, the Valve being urged into seating relation by the compression spring 88 supported in the enlarged lower end of the chamber i6. The valve may be actuated by a plunger 90 which extends through a gland nut 62 threaded into the upper end of the chamber l5, and is operatively connected, by suitable means, such as the pivoted links 94, with a hand lever 96. When the lever 9S is forced down manually the plunger 96 contacts the upper end of the valve stern 84 and moves the valve stem downwardly against the force of the spring 88 to unseat the plunger from the seat 86 and open the valve, thereby connecting the pressure line 518 with the transverse passage 8%) and chamber 82. The lever 96 is urged upwardly by a suitable 4 means, such as the spring 98, and may be latched in its downward position by the latch |00 cooperating with the pin 99. This latch may be manually disengaged by swinging the outer portion of the lever upwardly about the pivot |0| to move the tongue |82 against the hook I Im and force the lock out of engagement with the pin. When the valve 84-86 is open, the fluid under pressure will ilow through the conduit 58, through the valve and through the transverse passage 8E! into the chamber 82 where it will act against the undersurface of the piston |84 carried by the stem |86 reciprocably mounted in the chamber 82 and projecting at its upper end through the gland nut |88. The piston |84 is slightly smaller than the chamber 82 in which it is located to provide a restricted passage between the piston and the wall of the chamber, and is urged downwardly toward the limiting position illustrated in Fig. 4 by the compression spring |88. Fluid under pressure, flowing from the pressure line 58, through the valve 84-86 and through the transverse channel 80, flows between the piston |04 and the wall of the `chamber 82 to the upper part of the chamber feathered or unfeathered, this ow will continue as long as the piston 24 continues to move in the same direction. As soon as the piston reaches its limiting position, the flow will stop whereupon the pressure upon the opposite sides of the piston |04 will become equalized and the spring |68 will push the piston downwardly again to the position illustrated in Fig. 4. Upon its end extending through the gland nut |08', the stem |06 carries an abutment IIU which cooperates with a pin III carried by the latch I to move the latch clear of the pin 99 when the piston |84 moves downwardly, thereby releasing the hand lever 96 and permitting the spring 88 to close the valve 86 and discontinue the supply of pressure fluid to the propeller.

The plunger 90 is provided, on its inner end, with a valve I|2 which cooperates with avalve seat formed in the upper end of the plunger 84 and connected through the channel ||4 with the portion of the chamber 16 intercepted by the transverse channel 8D so that, when the hand lever 96 is in its upper position, as illustrated, the channel is connected through the channel |I4, valve ||2, port ||6 and drilled channels IIB and |28 with the drain line 64 to relieve the fluid pressure in the propeller pitch changing mechanism and in the valve I4 and the connecting line 68 after the propeller has been brought to its feathered position and the handle 96 released by the trip mechanism including the abutment IIB, pin III and the latch |08. The spaces at the lower ends of the stems 84 and |86 are continuously connected with the drain line through the drilled channels |22 and |24 and the ports |26 so that movements of these plungers will not be affected by fluid trapped in the closed ends of the respective chambers and the ends of the movable stems.

In the form of valve shown in Figs. 5 and 6 the arrangement of the control valve 84, spring 88, plunger 98, link 94, hand lever 96 and spring 98 is substantially the same as that described above. In this modified form of invention, however, a pressure responsive valve generally indicated at |28 is mounted in a chamber |30 which extends only partly through the valve casing 18 and is hydraulically disposed between the pressure line 58 and the chamber 16 containing the valve 84. When the handle 96 has been forced down and caught by the latch |32 the valve 86 will be open and the hydraulic fluid under pressure will iiow from the pressure line 58 through the valve 86 to the fluid conduit 68 leading to the propeller. The channel |25 will apply the iiuid pressure to the valve |28 to open this valve and move the plunger |34. While the pitch changing piston 24 is moving the increasing capacity of the space between the piston and the respective end of the cylinder 26 will prevent a rapid increase of the fluid pressure in the valve I4. As soon, however, as the piston stops, upon reaching its limiting position, the fluid pressure in the valve will immediately build up and force the plunger |34 and the valve |28 upwardly against the force of the compression spring |36. The upper end of the plunger |34 projects through the gland nut |38 and, upon upward movement of the plunger, will contact a portion |48 of the latch |32 and move the latch to release the hand lever 96 thereby closing the valve 86 and connecting the propeller supply line 63 with drain through the valve seat formed on the upper end of the plunger 84 and the drain line 64, the drain being cut off by the valve l I2 and the end of the plunger 90 when the lever 96 is down, as is particplarly illustrated in Fig, 6. In the modified arrangement the space below the plunger 84 is connected with drain by means of the ports |42 and the drilled channels |44 and |46.

In bringing the propeller to its feathered position, the propeller distributing valve 30 does not materially change its position since the necessary operation is to increase the pitch of the propeller by supplying high pressure fluid to the rearward or pitch increasing side of the piston 24 which .is the same side of the piston to which the governor actuated valve is connected. In order to feather the propeller the hand lever 96 is simply forced inwardly toward the valve casing 'I8 to apply the high pressure fluid from the source 6B to the above described side of the piston 24. The increase of fluid pressure in the line 68 will move the valve 18 to close off the governor channel l2 and connect the conduit 68 with the conduit 14 which connects with the collector ring 44 which in turn leads through the channel 42 to the distributing valve 3l! which, in the position shown in Fig. 2, causes the high pressure fluid to be applied to the left hand end of the piston 24 t0 increase the propeller pitch, the space of the right hand end of the piston 24 being connected with the engine lubricating system through the conduit 4l! so that fluid from this space may be vented through the lubricating system and the pressure release valve |48. As soon as the propeller has reached the feathered position, the hand lever will be released and the space at the left hand end of the piston 24 connected with drain, as described above, to relieve the fluid pressure on the piston and the connecting conduit. At the same time iiow of fluid from the pressure source 68 will be blocked by the closing of the valve 86.

When it is desired to return the propeller from its feathered position to the range in which it is under the control of the governor I2, the hand lever 96 must again be forced down to render the valve |4 operative to supply additional pressure iiuid to the propeller. Since the fluid pressure required to unfeather the propeller is greater than the pressure required to bring the propeller to a feathered position, the increased fluid pressure acting on the left hand end of the stem |58 of the distributing valve 30 will move the stem |50 against the force of the compression spring |52 to the position shown in Fig. 3 in which the channel 42 is connected by the valve passages 46 and 48 with the conduit 40 leading to the space at the pitch reducing end of the piston 24, and the conduit 42 is connected through the valve passages 36 and |54 and conduit 56 with the space at the pitch increasing side of the piston 24, thereby reversing the application of the pressure iiuid to the pitch changing piston.

If a valve of the kind shown in Figs. 5 and 6 is used, the handle 96 will have to be manually depressed until the propeller blades are started out of their feathered position after which the propeller will start to rotate or windmill and the action of centrifugal force on the blade plus the pressure of the fluid supplied through the conduit 40 will quickly reduce the pitch to the constant speed range. The lock |32, however, will not be operative to hold the lever 96 down because the unfeathering pressure is sufficient to compress the spring |36 and move the plunger |34 upwardly to maintain the latch in an inoperative position.

If the form of valve shown in Fig. 4 is used, the latch |86 will be operative since it will not be disengaged by the abutment member l 0 until the fluid iiow through the propeller shall have been started and stopped again. With this form of valve the handle 98 would be locked down to bring the propeller out of the feathered position and would be retained in its downward position to hold the valve 86 open until the piston 24 had reached its limiting low pitch position at which time flow of pressure fluid from the source 60 to the propeller would be stopped and the latch mechanism would act to release the lever and close the valve 83 and open the valve l2 thereby relieving the pressure in the line 68 and permitting the valve 'lllv to change the connection of the line T4 from the line 68 to the channel 'l2 and restore the propeller to governor control.

While a complete propeller control system has been somewhat diagrammatically illustrated, and two somewhat different forms of propeller feathering and unfeathering control valves have been particularly illustrated, and hereinabove described for the purpose of disclosing the invention, it is to be understood that the invention is not limited to the particular constructions so illustrated and described, but that such changes in the size, shape and arrangement of the various parts may be resorted to as come withinY the scope of the sub-joined claims.

Having now described the invention so that others skilled in the art may clearly understand the same, what it is desired to secure by Letters Patent is as follows:

1. A control including a body formed with inlet and outlet openings and a discharge opening, and passages connecting the same, a valve interposed between said inlet and outlet openings and cooperable with a seat to prevent a ilow of fluid fromone opening to the other, a sealing portieri coupled to said valve and formed with an opening through its body, such opening affording communication between said outlet opening and said discharge opening, a further valve body normally spaced from and movable into contact with said sealing portion to seal the opening therethrough, means coupled to said further valve to cause the same to engage said portion to move the valve connected to said portion to a position such that fluid may flow from said inlet to said outlet opening, said body being formed with a bore, a piston slidable within said bore, said bore being coupled to said passages at a point beyond said first named valve and means controlled by said piston to render said last named means inoperative.

2. A control including a body formed with inlet and outlet openings and a discharge opening, and passages connecting the same, a valve interposed between said inlet and outlet openings and cooperable with a seat to prevent a ow of fluid from one opening to the other, a sealing portion coupled to said valve and formed with an opening through its body, such opening affording communication between said outlet opening and said discharge opening, a further valve body normally spaced from and movable into contact with said sealing portion to seal the opening therethrough, means coupled to said further valve to cause the same to engage said portion to move the valve connected to said portion to a position such that fluid may ow from said inlet to said outlet opening, a latch engageable with said last named means to retain the same against movement, said body being formed with a bore, a piston slidable within said bore, means connected to said piston and engageable with said latch to render the latter inoperative and said bore being connected to a passage within said body at a point beyond said first named valve.

3. A control including a body formed with inlet and outlet openings and a discharge opening, and passages connecting the same, a valve interposed between said inlet and outlet openings, and cooperable with a seat to prevent a ow of fluid from one opening to the other, a sealing portion coupled to said valve and formed with an opening through its body, such opening aording communication between said outlet opening and said discharge opening, a further valve body normally spaced from and movable into contact with said sealing portion to seal the opening therethrough, means coupled to said further valve to cause the same to engage said portion to move the valve connected to said portion to a position such that uid may ow from said inlet to said outlet opening, a latch engageable with said last named means to retain the same against movement, said body being formed with a bore, a piston slidable within said bore, means connected to said piston and engageable with said latch to render the latter inoperative, said piston being formed with a passage, avalve for controlling the flow of liquid to the base of said piston, said piston-receiving bore being connected to said discharge opening and said bore being also connected by a passage within said body to a point beyond said first named valve.

4. Means for controlling the operation of a hydraulic motor comprising, a pressure responsive reversing valve in the connection between` a source of ,igh pressure hydraulic uid and said motor and operable to change the connection from one side of said rnotor to the other side when the pressure of said fluid on said valve exceeds a predetermined amount, a control valve in said connection between said reversing valve and said source, manually operable means for opening said control valve and releasable means for holding said control valve open, and means responsive to a change, downstream of said control valve, in the force producing properties of said motor operating fluid and incident to positioning said motor at its terminal position for preventing reversal of said motor comprising, means automatically releasing said holding means and closing said control valve when said motor reaches a terminal position, said releasing means being actuatable by a change in the force producing properties of said motor operating uid insufcient to operate said reversing valve.

5. A fluid supply control comprising, a casing having a fluid inlet and a fluid outlet connection, a valve in said casing between said connections, a spring urging said valve to closed position, manual means for opening said valve, means for releasably holding said valve open, means responsive to a change in a, characteristic of the fluid flowing through said valve to release said holding means, such change in the uid characteristic being due to a rise in pressure in said outlet connection, a fluid directing valve connected with said uid outlet for directing the uid from said outlet to either of two discharge lines and operable by an increase in the fluid outlet pressure above a preselected value to disconnect one discharge line and connect the other .discharge line with said outlet, said means to release said holding means being operative to render said spring effective to close said valve when the fluid pressure in said outlet connection exceeds a predetermined value less than said preselected value and thus prevent said directing valve from changing discharge lines.

ERLE MARTIN.

REFERENCES CITED The following references are of record in the le of this patent:

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